Enterprises as well as individuals are becoming increasingly dependent on computers. As more and more data are generated, the need for efficient and reliable data backup storage systems is increasing. There are a variety of systems in existence today, utilizing both local and remote storage for backup. Some backup systems use both a local backup system and a replica backup system in a remote location in order to ensure the safety of the data. Synchronization of the local system and the replica system can be simplified by using the network to transmit data from the local system to the replica system. However, for large systems, speed of data transmission can limit the feasibility of network backup replication.